When testing a diode with a multimeter, which observation indicates the diode is functioning properly?

When testing a diode with a multimeter, which observation indicates the diode is functioning properly?

• A. Reverse bias conducts.
• B. Forward bias conducts.
• C. Both forward and reverse biases conduct.
• D. Forward bias conducts and reverse bias does not conduct.

Answer: (D)

A functioning diode passes current when forward-biased and blocks current when reverse-biased. When you test with a multimeter, applying a small forward voltage across the diode (red lead on the anode, black on the cathode) should produce a forward voltage reading and current flow. In the reverse orientation, the diode should block current, so the meter shows little to no current (often displaying OL or a very high resistance). This combination—current flow in the forward direction and no current in the reverse direction—indicates the diode is working properly. If current appears in reverse or is absent in forward, the diode would be faulty.

A functioning diode passes current when forward-biased and blocks current when reverse-biased. When you test with a multimeter, applying a small forward voltage across the diode (red lead on the anode, black on the cathode) should produce a forward voltage reading and current flow. In the reverse orientation, the diode should block current, so the meter shows little to no current (often displaying OL or a very high resistance). This combination—current flow in the forward direction and no current in the reverse direction—indicates the diode is working properly. If current appears in reverse or is absent in forward, the diode would be faulty.